LASER BASED METHYL RADICAL MONITORING FOR PROCESS CONTROL IN DIAMOND CVD DEPOSITION

THE METHYL RADICAL IS A KEY SPECIES IN THE FORMATION OF CVD DIAMOND, FOR WHICH THERE IS A NEED FOR AN ON-LINE MONITOR USABLE IN INDUSTRIAL PRODUCTION OF CVD DIAMOND. WE PROPOSE TO MONITORMETHYL RADICAL CONCENTRATIONS USING THE ABSORPTION OF THE INFRARED OUTPUT OF A NEUTRAL XENON LASER AT 3217.75 WAVENUMBERS. THE PHASE I EXPERIMENTS WILL MEASURE THIS ABSORPTION IN AN RF METHANE PLASMA, IN WHICH METHYL RADICAL CONCENTRATION IS MEASURED USING A PREVIOUSLY CALIBRATED ABSORPTION LINE NEAR 608 WAVENUMBERS. ANTICIPATED BENEFITS/POTENTIAL COMMERCIAL APPLICATIONS - THE PROPOSED METHYL RADICAL MONITOR WOULD BE USED FOR ON-LINE QUALITY CONTROL OF THE DIAMOND DEPOSITION PROCESS. USING OTHER LASER LINES, A SIMILAR MONITOR COULD BE USED FOR OTHER MOLECULAR SPECIES.